The effects of advancement of the tibial tuberosity by inserting bony wedges was studied on cadaveric specimens of the knee. The geometry, the contact areas and the forces acting on the patellofemoral joint were investigated, and the forces acting on the tibiofemoral compartment were calculated. A 1 cm advancement was found to be optimal in reducing the high patellofemoral joint forces occurring at 90 degrees and 110 degrees of flexion, whilst causing least reduction of the contact areas; the stresses on the joint were reduced significantly. Advancement by 2 cm and by 3 cm drastically reduced the congruity and the size of the contact area. It was also shown that 2 cm and 3 cm advancement caused an increase in forces at the patellofemoral joint and also in the tibiofemoral joint in a direction tangential to the articular surfaces.
The off-loading characteristics of the cast-braces of 30 patients with fractures of the shaft of the femur have been investigated, during axial loading, using strain-gauge transducers. These were applied at the level of the fracture, where the cast was circumferentially split, and to the hinges of the brace at the knee. They measured the load transferred between the two portions of the thigh cast, and between the thigh cast as a whole and the below-knee cast; by subtraction from the total load on the limb, the skeletal force at the fracture level and at the knee could be calculated. In all patients there was an increase in the fracture load as union progressed which was thought to be due to physiological feedback mechanism from the fracture site. The load carried by the two portions of the thigh cast and by the thigh cast as a whole was proportionately high at first and stabilised at an average of 35 per cent of body weight.
In 65 mature Wistar rats a Kirschner wire was introduced into the medullary cavity of each femur. A closed transverse mid-shaft fracture of one femur was produced by a three-point bending technique. Subsequently the mechanical characteristics of the healing fracture, including the torque and angle of twist required to take the callus to its yield point and to ultimate failure, were compared with those for the opposite femur of each rat. Controls were killed in groups at two, three, four, five and seven weeks. Test animals were given bovine growth hormone in a daily dose of five milligrams before being killed in groups at two, three and four weeks. A significant increase in torque index was found in the two-week group of test animals but not in subsequent groups. No evidence was found that growth hormone given alone could produce an overall shortening of the healing time in fresh fractures.
Nine patients with nonunited humeral shaft fractures were treated by open reduction and internal fixation with an intramedullary fibular bone graft and a compression plate. Fixation of the screws was enhanced by passing them through the fibula as well as the two humeral cortices (quadricortical fixation). Eight of the nine fractures united at an average of 3.5 months. Tests on cadaver bones showed that quadricortical fixation was as strong as methylmethacrylate augmentation and significantly better than bicortical fixation.
Using 26 cadaver shoulders, we produced a standard defect in the supraspinatus tendon and performed one of three types of repair. Their strength was found by testing in tension the force required to produce a gap of 3 mm, then 6 mm, and finally total disruption of the repair. The use of a polyethylene patch to spread the forces over the lateral bone surface and of extra sutures to grasp the tendon end raised by 2.6 times the load at which a 3 mm gap in the repair occurred and by 1.7 times the load to failure.
To investigate the origin of fractures at the distal locking site of the Gamma nail, we loaded ten paired human cadaver femora fixed with a Gamma nail in torsion until they fractured. When an awl was hammered in to start the hole for distal locking a fissure appeared in the lateral cortex of all the femora, and the mean torsional load to create a fracture was reduced by 57.8% compared with that in a control group in which the distal locking hole had been started with a centre drill. When an additional drill hole was made, the mean failure load in torsion decreased by 35.7%. We strongly recommend that an awl should not be used at the distal locking site of the Gamma nail; we recommend the use of a centre drill. Additional drill holes should be avoided because they act as stress raisers.
A cadaver study was performed to determine the effect of arm position and capsular release on rotator cuff repair. Artificial defects were made in the rotator cuff to include only the supraspinatus (small) or both supraspinatus and infraspinatus (large). The defects were repaired in a standard manner with the shoulder abducted 30 degrees at the glenohumeral joint. Strain gauges were placed on the lateral cortex of the greater tuberosity and measurements were recorded in 36 different combinations of abduction, flexion/extension, and medial/lateral rotation. Readings were obtained before and after capsular release. With small tears, tension in the repair increased significantly with movement from 30 degrees to 15 degrees of abduction (p <
0.01) but was minimally affected by changes in flexion or rotation. Capsular release significantly reduced the force (p <
0.01) at 0 degree and 15 degrees abduction. For large tears, abduction of 30 degrees or more with lateral rotation and extension consistently produced the lowest values. Capsular release resulted in 30% less force at 0 degree abduction (p <
0.05).
We report the experimental use of three different biological implants to restore articular surface defects: glutaraldehyde-fixed bovine meniscal xenograft, glutaraldehyde-fixed bovine costal cartilage xenograft, and viable osteochondral allografts. The grafts were implanted in the knees of 19 goats who were allowed free-field activity and were studied for up to one year. The natural articular surfaces of meniscal fibrocartilage provided excellent articular surfaces at all times. Equally good articular surfaces were restored by host tissue growth covering costal cartilage grafts at six months, but by 12 months this surface had degenerated. The majority of the allografts survived and integrated with the host at six months, but many showed signs of failure at 12 months. Only three out of seven ungrafted defects healed completely at six months and the healed surfaces were degenerating at 12 months.
Excessive foot pronation has been considered to be related to anterior knee pain. We undertook a prospective study to test the hypothesis that exertional anterior knee pain is related to the static and dynamic parameters of foot pronation. Two weeks before beginning basic training lasting for 14 weeks, 473 infantry recruits were enrolled into the study and underwent two-dimensional measurement of their subtalar joint displacement angle during walking on a treadmill. Of the 405 soldiers who finished the training 61 (15%) developed exertional anterior knee pain. No consistent association was found between the incidence of anterior knee pain and any of the parameters of foot pronation. While a statistically significant association was found between anterior knee pain and pronation velocity (left foot, p = 0.05; right foot, p = 0.007), the relationship was contradictory for the right and left foot. Our study does not support the hypothesis that anterior knee pain is related to excessive foot pronation.
This article is a systematic review of the published
literature about the biomechanics, functional outcome and complications
of intramedullary nailing of fractures of the distal radius. We searched the Medline and EMBASE databases and included all
studies which reported the outcome of intramedullary (IM) nailing
of fractures of the distal radius. Data about functional outcome,
range of movement (ROM), strength and complications, were extracted.
The studies included were appraised independently by both authors
using a validated quality assessment scale for non-controlled studies
and the CONSORT statement for randomised controlled trials (RCTs). The search strategy revealed 785 studies, of which 16 were included
for full paper review. These included three
Polished taper-slip (PTS) cemented stems have an excellent clinical track record and are the most common stem type used in primary total hip arthroplasty (THA) in the UK. Due to low rates of aseptic loosening, they have largely replaced more traditional composite beam (CB) cemented stems. However, there is now emerging evidence from multiple joint registries that PTS stems are associated with higher rates of postoperative periprosthetic femoral fracture (PFF) compared to their CB stem counterparts. The risk of both intraoperative and postoperative PFF remains greater with uncemented stems compared to either of these cemented stem subtypes. PFF continues to be a devastating complication following primary THA and is associated with high complication and mortality rates. Recent efforts have focused on identifying implant-related risk factors for PFF in order to guide preventative strategies, and therefore the purpose of this article is to present the current evidence on the effect of cemented femoral stem design on the risk of PFF. Cite this article:
The aim of this study was to compare the clinical and radiological outcomes of reverse shoulder arthroplasty (RSA) using small and standard baseplates in Asian patients, and to investigate the impact of a mismatch in the sizes of the glenoid and the baseplate on the outcomes. This was retrospective analysis of 50 and 33 RSAs using a standard (33.8 mm, ST group) and a small (29.5 mm, SM group) baseplate of the Equinoxe reverse shoulder system, which were undertaken between January 2017 and March 2021. Radiological evaluations included the size of the glenoid, the Aims
Methods
Despite being one of the most common injuries around the elbow, the optimal treatment of olecranon fractures is far from established and stimulates debate among both general orthopaedic trauma surgeons and upper limb specialists. It is almost universally accepted that stable non-displaced fractures can be safely treated nonoperatively with minimal specialist input. Internal fixation is recommended for the vast majority of displaced fractures, with a range of techniques and implants to choose from. However, there is concern regarding the complication rates, largely related to symptomatic metalwork resulting in high rates of implant removal. As the number of elderly patients sustaining these injuries increases, we are becoming more aware of the issues associated with fixation in osteoporotic bone and the often fragile soft-tissue envelope in this group. Given this, there is evidence to support an increasing role for nonoperative management in this high-risk demographic group, even in those presenting with displaced and/or multifragmentary fracture patterns. This review summarizes the available literature to date, focusing predominantly on the management techniques and available implants for stable fractures of the olecranon. It also offers some insights into the potential avenues for future research, in the hope of addressing some of the pertinent questions that remain unanswered. Cite this article:
Injury to the triangular fibrocartilage complex (TFCC) may result in ulnar wrist pain with or without instability. One component of the TFCC, the radioulnar ligaments, serve as the primary soft-tissue stabilizer of the distal radioulnar joint (DRUJ). Tears or avulsions of its proximal, foveal attachment are thought to be associated with instability of the DRUJ, most noticed during loaded pronosupination. In the absence of detectable instability, injury of the foveal insertion of the radioulnar ligaments may be overlooked. While advanced imaging techniques such as MRI and radiocarpal arthroscopy are well-suited for diagnosing central and distal TFCC tears, partial and complete foveal tears without instability may be missed without a high degree of suspicion. While technically challenging, DRUJ arthroscopy provides the most accurate method of detecting foveal abnormalities. In this annotation the spectrum of foveal injuries is discussed and a modified classification scheme is proposed. Cite this article:
Periprosthetic femoral fracture (PPF) is a major complication following total hip arthroplasty (THA). Uncemented femoral components are widely preferred in primary THA, but are associated with higher PPF risk than cemented components. Collared components have reduced PPF rates following uncemented primary THA compared to collarless components, while maintaining similar prosthetic designs. The purpose of this study was to analyze PPF rate between collarless and collared component designs in a consecutive cohort of posterior approach THAs performed by two high-volume surgeons. This retrospective series included 1,888 uncemented primary THAs using the posterior approach performed by two surgeons (PKS, JMV) from January 2016 to December 2022. Both surgeons switched from collarless to collared components in mid-2020, which was the only change in surgical practice. Data related to component design, PPF rate, and requirement for revision surgery were collected. A total of 1,123 patients (59.5%) received a collarless femoral component and 765 (40.5%) received a collared component. PPFs were identified using medical records and radiological imaging. Fracture rates between collared and collarless components were analyzed. Power analysis confirmed 80% power of the sample to detect a significant difference in PPF rates, and a Fisher’s exact test was performed to determine an association between collared and collarless component use on PPF rates.Aims
Methods
Obtaining solid implant fixation is crucial in revision total knee arthroplasty (rTKA) to avoid aseptic loosening, a major reason for re-revision. This study aims to validate a novel grading system that quantifies implant fixation across three anatomical zones (epiphysis, metaphysis, diaphysis). Based on pre-, intra-, and postoperative assessments, the novel grading system allocates a quantitative score (0, 0.5, or 1 point) for the quality of fixation achieved in each anatomical zone. The criteria used by the algorithm to assign the score include the bone quality, the size of the bone defect, and the type of fixation used. A consecutive cohort of 245 patients undergoing rTKA from 2012 to 2018 were evaluated using the current novel scoring system and followed prospectively. In addition, 100 first-time revision cases were assessed radiologically from the original cohort and graded by three observers to evaluate the intra- and inter-rater reliability of the novel radiological grading system.Aims
Methods
Dual-mobility (DM) components are increasingly used to prevent and treat dislocation after total hip arthroplasty (THA). Intraprosthetic dissociation (IPD) is a rare complication of DM that is believed to have decreased with contemporary implants. This study aimed to report incidence, treatment, and outcomes of contemporary DM IPD. A total of 1,453 DM components were implanted at a single academic institution between January 2010 and December 2021: 695 in primary and 758 in revision THA. Of these, 49 presented with a dislocation of the large DM head and five presented with an IPD. At the time of closed reduction of the large DM dislocation, six additional IPDs occurred. The mean age was 64 years (SD 9.6), 54.5% were female (n = 6), and mean follow-up was 4.2 years (SD 1.8). Of the 11 IPDs, seven had a history of instability, five had abductor insufficiency, four had prior lumbar fusion, and two were conversions for failed fracture management.Aims
Methods
The aim of this retrospective study was to assess the incidence of early periprosthetic femoral fracture (PFF) associated with Charnley-Kerboull (CK) femoral components cemented according to the ‘French paradox’ principles through the Hueter anterior approach (HAA) in patients older than 70 years. From a prospectively collected database, all short CK femoral components implanted consecutively from January 2018 to May 2022 through the HAA in patients older than 70 years were included. Exclusion criteria were age below 70 years, use of cementless femoral component, and approaches other than the HAA. A total of 416 short CK prostheses used by 25 surgeons with various levels of experience were included. All patients had a minimum of one-year follow-up, with a mean of 2.6 years (SD 1.1). The mean age was 77.4 years (70 to 95) and the mean BMI was 25.3 kg/m2 (18.4 to 43). Femoral anatomy was classified according to Dorr. The measured parameters included canal flare index, morphological cortical index, canal-calcar ratio, ilium-ischial ratio, and anterior superior iliac spine to greater trochanter (GT) distance.Aims
Methods
Surgical approaches that claim to be minimally invasive, such as the direct anterior approach (DAA), are reported to have a clinical advantage, but are technically challenging and may create more injury to the soft-tissues during joint exposure. Our aim was to quantify the effect of soft-tissue releases on the joint torque and femoral mobility during joint exposure for hip resurfacing performed via the DAA. Nine fresh-frozen hip joints from five pelvis to mid-tibia cadaveric specimens were approached using the DAA. A custom fixture consisting of a six-axis force/torque sensor and motion sensor was attached to tibial diaphysis to measure manually applied torques and joint angles by the surgeon. Following dislocation, the torques generated to visualize the acetabulum and proximal femur were assessed after sequential release of the joint capsule and short external rotators.Aims
Methods
Revision total hip arthroplasty in patients with Vancouver type B3 fractures with Paprosky type IIIA, IIIB, and IV femoral defects are difficult to treat. One option for Paprovsky type IIIB and IV defects involves modular cementless, tapered, revision femoral components in conjunction with distal interlocking screws. The aim of this study was to analyze the rate of reoperations and complications and union of the fracture, subsidence of the stem, mortality, and the clinical outcomes in these patients. A total of 46 femoral components in patients with Vancouver B3 fractures (23 with Paprosky type IIIA, 19 with type IIIB, and four with type IV defects) in 46 patients were revised with a transfemoral approach using a modular, tapered, cementless revision Revitan curved femoral component with distal cone-in-cone fixation and prospectively followed for a mean of 48.8 months (SD 23.9; 24 to 112). The mean age of the patients was 80.4 years (66 to 100). Additional distal interlocking was also used in 23 fractures in which distal cone-in-cone fixation in the isthmus was < 3 cm.Aims
Methods